Powder base

Once the marketing questions had been answered, a cosmetic chemist had to formulate a powder that met the qualities needed. Leaving aside decisions about what perfume to use or what shades to make, the remaining qualities of a face powder were determined by the white or off-white ingredients that made up what is sometimes referred to as the powder base. These affected the basic characteristics of the face powder including texture, covering power, staying power, absorption properties and ease of application.

Covering power

The main function of early face powders was to visually cover the skin, so that shine was reduced and imperfections were hidden. The amount of concealment needed varied from woman to woman, so powders were produced in various grades loosely referred to as light, medium and heavy.

The types of skin which face powders must cover are dry, normal, moderately oily, very oily. Because dry skin secretes very little moisture and no oil, it requires a powder of light covering power. Normal and moderately oily skins, being more shiny due to secretion of oil and moisture, require a powder with more covering power. Very oily skins having a high shine require a powder of special covering power.

(Thomssen, 1947, p. 48)

Although the idea of linking covering power with oil absorbency was followed for many years, it was overly simplistic. First, selection of a powder with a suitable covering power often had more to do with fashion than with skin type – compare the use of more opaque powders of the 1930s with the transparent powders of the 1970s – and second, younger skins with a higher oil content generally show fewer blemishes than older skins with a lower oil content. Taking just these two factors into account, it seems better to separate the ability of a face powder to hide imperfections (covering power) from its capacity to reduce shine (absorbency) and this was the direction most cosmetic chemists eventually took.

Above: Testing the covering power of various concentrations of zinc oxide (deNavarre, 1941).

Zinc oxide, kaolin, magnesium oxide and starch were all used to improve the covering power of early face powders but their effects were not as strong as titanium dioxide, a brilliant, white, inert powder. It began to be widely used in face powders in the early 1930s and it proved to be three to four times better than zinc oxide as a covering agent (deNavarre, 1941). When titanium dioxide was used in varying amounts with zinc oxide, any grade of powder could be produced.

White base for light powders with zinc oxide